<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    div{
      width: 200px;
      height: 200px;
      border: solid 1px #999;
    }
  </style>
</head>
<body>
  <button>点击发送请求</button>
  <div></div>
  <script>
    let btn = document.querySelector('button')

    btn.onclick = function(){
      let xhr = new XMLHttpRequest();
      xhr.open('get', 'http://192.168.20.111/api');
      xhr.send();
      xhr.onload = function(){
        console.log(xhr.response);
      }
    }
  </script>
</body>
</html>